scholarly journals Autism Spectrum Disorder and the Gut Microbiota in Children: A Systematic Review

2020 ◽  
Vol 76 (1) ◽  
pp. 16-29 ◽  
Author(s):  
Navya Bezawada ◽  
Tze Hui Phang ◽  
Georgina L. Hold ◽  
Richard Hansen
Keyword(s):  
Autism Spectrum Disorder ◽  
Gut Microbiota ◽  
Meta Analysis ◽  
Gastrointestinal Symptoms ◽  
Autism Spectrum ◽  
Spectrum Disorder ◽  
Extensive Literature ◽  
Faecal Samples ◽  
Extensive Literature Search

Introduction: Differences in microbiota composition in children with autism spectrum disorder (ASD) compared to unaffected siblings and healthy controls have been reported in various studies. This study aims to systematically review the existing literature concerning the role of the gut microbiota in ASD. Methods: An extensive literature search was conducted using MEDLINE and EMBASE databases to identify studies (January 1966 through July 2019). Results: A total of 28 papers were included. The studies ranged from 12 to 104 participants who were aged between 2 and 18 years from various geographical areas. Majority of studies included faecal samples; however, 4 studies examined mucosal biopsies from different sites. The heterogeneity in ASD diagnostic methodology, gut site sampled and laboratory methods used made meta-analysis inappropriate. Species reported to be significantly higher in abundance in autistic children included Clostridium, Sutterella, Desulfovibrio and Lactobacillus. The findings are however inconsistent across studies. In addition, ­potential confounding effects of antimicrobial use, gastrointestinal symptoms and diet on the gut microbiota are unclear due to generally poor assessment of these factors. Conclusion: It is clear that the gut microbiota is altered in ASD, although further exploration is needed on whether this is a cause or an effect of the condition.

scholarly journals A systematic review and meta-analysis of studies on metaphor comprehension in individuals with autism spectrum disorder: Do task properties matter?

2019 ◽  
Vol 40 (6) ◽  
pp. 1421-1454 ◽  
Author(s):  
Tamar Kalandadze ◽  
Valentina Bambini ◽  
Kari-Anne B. Næss
Keyword(s):  
Systematic Review ◽  
Autism Spectrum Disorder ◽  
Syntactic Structure ◽  
Meta Analysis ◽  
Autism Spectrum ◽  
Spectrum Disorder ◽  
Response Format ◽  
Metaphor Comprehension ◽  
The Relationship

AbstractIndividuals with autism spectrum disorder (ASD) often experience difficulty in comprehending metaphors compared to individuals with typical development (TD). However, there is a large variation in the results across studies, possibly related to the properties of the metaphor tasks. This preregistered systematic review and meta-analysis (a) explored the properties of the metaphor tasks used in ASD research, and (b) investigated the group difference between individuals with ASD and TD on metaphor comprehension, as well as the relationship between the task properties and any between-study variation. A systematic search was undertaken in seven relevant databases. Fourteen studies fulfilled our predetermined inclusion criteria. Across tasks, we detected four types of response format and a great variety of metaphors in terms of familiarity, syntactic structure, and linguistic context. Individuals with TD outperformed individuals with ASD on metaphor comprehension (Hedges’ g = −0.63). Verbal explanation response format was utilized in the study showing the largest effect size in the group comparison. However, due to the sparse experimental manipulations, the role of task properties could not be established. Future studies should consider and report task properties to determine their role in metaphor comprehension, and to inform experimental paradigms as well as educational assessment.

scholarly journals Composition of Gut Microbiota in Children with Autism Spectrum Disorder: A Systematic Review and Meta-Analysis

Nutrients ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 792 ◽  
Author(s):  
Lucía Iglesias-Vázquez ◽  
Georgette Van Ginkel Riba ◽  
Victoria Arija ◽  
Josefa Canals
Keyword(s):  
Autism Spectrum Disorder ◽  
Gut Microbiota ◽  
Psychiatric Symptoms ◽  
Meta Analysis ◽  
Public Health Problem ◽  
Autism Spectrum ◽  
Spectrum Disorder ◽  
Lower Percentage ◽  
Children With Asd ◽  
Meta Analyses

Background: Autism spectrum disorder (ASD) is a public health problem and has a prevalence of 0.6%–1.7% in children. As well as psychiatric symptoms, dysbiosis and gastrointestinal comorbidities are also frequently reported. The gut–brain microbiota axis suggests that there is a form of communication between microbiota and the brain underlying some neurological disabilities. The aim of this study is to describe and compare the composition of gut microbiota in children with and without ASD. Methods: Electronic databases were searched as far as February 2020. Meta-analyses were performed using RevMan5.3 to estimate the overall relative abundance of gut bacteria belonging to 8 phyla and 17 genera in children with ASD and controls. Results: We included 18 studies assessing a total of 493 ASD children and 404 controls. The microbiota was mainly composed of the phyla Bacteroidetes, Firmicutes, and Actinobacteria, all of which were more abundant in the ASD children than in the controls. Children with ASD showed a significantly higher abundance of the genera Bacteroides, Parabacteroides, Clostridium, Faecalibacterium, and Phascolarctobacterium and a lower percentage of Coprococcus and Bifidobacterium. Discussion: This meta-analysis suggests that there is a dysbiosis in ASD children which may influence the development and severity of ASD symptomatology. Further studies are required in order to obtain stronger evidence of the effectiveness of pre- or probiotics in reducing autistic behaviors.

Treating autism spectrum disorder by intervening with gut microbiota

2021 ◽  
Vol 70 (12) ◽  
Author(s):  
Tingting Tu ◽  
Changlin Zhao
Keyword(s):  
Autism Spectrum Disorder ◽  
Gut Microbiota ◽  
Ketogenic Diet ◽  
Gastrointestinal Symptoms ◽  
Autism Spectrum ◽  
Formula Feeding ◽  
Spectrum Disorder ◽  
Human Cognition ◽  
The Core ◽  
Randomized Controlled

Autism spectrum disorder (ASD) comprises a group of neurodevelopmental disorders with a high prevalence in childhood. The gut microbiota can affect human cognition and moods and has a strong correlation with ASD. Microbiota transplantation, including faecal microbiota transplantation (FMT), probiotics, breastfeeding, formula feeding, gluten-free and casein-free (GFCF) diet and ketogenic diet therapy, may provide satisfying effects for ASD and its related various symptoms. For instance, FMT can improve the core symptoms of ASD and gastrointestinal symptoms. Probiotics, breastfeeding and formula feeding, and GFCF diet can improve gastrointestinal symptoms. The core symptom score still needs to be confirmed by large-scale clinical randomized controlled studies. It is recommended to use a ketogenic diet to treat patients with epilepsy in ASD. At present, the unresolved problems include which of gut the microbiota are beneficial, which of the microorganisms are harmful, how to safely and effectively implant beneficial bacteria into the human body, and how to extract and eliminate harmful microorganisms before transplantation. In future studies, large sample and randomized controlled clinical studies are needed to confirm the mechanism of intestinal microorganisms in the treatment of ASD and the method of microbial transplantation.

scholarly journals Role of the Gut Microbiota in the Pathophysiology of Autism Spectrum Disorder: Clinical and Preclinical Evidence

2020 ◽  
Vol 8 (9) ◽  
pp. 1369 ◽  
Author(s):  
Léa Roussin ◽  
Naika Prince ◽  
Paula Perez-Pardo ◽  
Aletta D. Kraneveld ◽  
Sylvie Rabot ◽  
...  
Keyword(s):  
Autism Spectrum Disorder ◽  
Gut Microbiota ◽  
Clinical Studies ◽  
Neurodevelopmental Disorder ◽  
Autism Spectrum ◽  
Spectrum Disorder ◽  
Preclinical Studies ◽  
Potential Implication ◽  
Gi Symptoms

Autism spectrum disorder (ASD) is a neurodevelopmental disorder affecting 1 in 160 people in the world. Although there is a strong genetic heritability to ASD, it is now accepted that environmental factors can play a role in its onset. As the prevalence of gastrointestinal (GI) symptoms is four-times higher in ASD patients, the potential implication of the gut microbiota in this disorder is being increasingly studied. A disturbed microbiota composition has been demonstrated in ASD patients, accompanied by altered production of bacterial metabolites. Clinical studies as well as preclinical studies conducted in rodents have started to investigate the physiological functions that gut microbiota might disturb and thus underlie the pathophysiology of ASD. The first data support an involvement of the immune system and tryptophan metabolism, both in the gut and central nervous system. In addition, a few clinical studies and a larger number of preclinical studies found that modulation of the microbiota through antibiotic and probiotic treatments, or fecal microbiota transplantation, could improve behavior. Although the understanding of the role of the gut microbiota in the physiopathology of ASD is only in its early stages, the data gathered in this review highlight that this role should be taken in consideration.

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